Warning: The above video may be graphic for some viewers. Viewer discretion is advised.Nashville Police released chilling surveillance video of a suspect who shot through the doors of a Christian elementary school and killed three children and three adults on Monday.Police say the 28-year-old shooter was behind the wheel of a car seen driving up to the Covenant School.Video shows the suspect pulling around to park, and 10 minutes later, a video from inside the school shows the suspect firing multiple shots through the glass doors of the school and crawling through to get inside.Police said the suspect was armed with three guns, two of which were assault-type weapons.Responding officers fatally shot the suspect.Police believe the shooter may be a former student and planned the massacre by drawing out a detailed map and conducting surveillance of the building.Nashville police also released body camera video Tuesday morning of police confronting the shooter at the school. The two angles show officers clearing school classrooms and hallways before encountering and shooting the perpetrator on an upstairs floor.Police gave unclear information on the gender of the shooter. For hours, police identified the shooter as a 28-year-old woman and eventually as Audrey Elizabeth Hale. At a late afternoon press conference, the police chief said Hale was transgender. After the news conference, police spokesperson Don Aaron declined to elaborate on how Hale identified. The Associated Press contributed to this report.